Seasonal hydrologic responses to climate change in the Pacific Northwest

Abstract

Increased temperatures and changes in precipitation will result in fundamental changes in the seasonal distribution of streamflow in the Pacific Northwest and will have serious implications for water resources management. To better understand local impacts of regional climate change, we conducted model experiments to determine hydrologic sensitivities of annual, seasonal, and monthly runoff to imposed annual and seasonal changes in precipitation and temperature. We used the Variable Infiltration Capacity (VIC) land-surface hydrology model applied at 1/16 latitude-longitude spatial resolution over the Pacific Northwest (PNW), a scale sufficient to support analyses at the hydrologic unit code eight (HUC-8) basin level. These experiments resolve the spatial character of the sensitivity of future water supply to precipitation and temperature changes by identifying the seasons and locations where climate change will have the biggest impact on runoff. The PNW exhibited a diversity of responses, where transitional (intermediate elevation) watersheds experience the greatest seasonal shifts in runoff in response to cool season warming. We also developed a methodology that uses these hydrologic sensitivities as basin-specific transfer functions to estimate future changes in long-term mean monthly hydrographs directly from climate model output of precipitation and temperature. When principles of linearity and superposition apply, these transfer functions can provide feasible first-order estimates of the likely nature of future seasonal streamflow change without performing downscaling and detailed model simulations.

Stressors and Strategies for Managing Urban Water Scarcity: Perspectives from the Field

“…However, the local politics of water management is complex and is often based on accepted behaviors and organizational cultures [38]. The pressing challenges of climate change and precipitation uncertainty pose formidable challenges to traditional approaches.…”

“…Although inadequate access to water sources was not rated highly as a cause of stress, there was general agreement in Phoenix that acquiring new sources of water would be a highly effective strategy: half of Phoenix water managers ranked this a 10/10. We note that while many of these strategies were supported, recent research from California suggest that applications of water efficient technology, increasing the prices of water and education [38], may not be highly effective. Generally, land-use planners were relatively more supportive than water managers of strategies in their field, such as limiting new growth, and more dense and compact communities.…”

Selecting climate change scenarios using impact‐relevant sensitivities

“…We calculated hydrologic sensitivities (S q , ε q ) in different seasons using the variable infiltration capacity (VIC) hydrologic model [Liang et al, 1994] configured for the PNW as in Vano et al [2015]. Spatially uniform T and P perturbations were applied independently to every day of a historical data set [Elsner et al, 2010;Hamlet et al, 2013] used as meteorological forcings for the VIC model.…”

Responses of runoff to historical and future climate variability over China

“…R) under future climate change scenarios. However, the key issue faced by such studies is the need to convert coarseresolution GCM outputs to local catchment-scale climatic variables at a higher spatial resolution to serve as the input to a hydrological model (Vano et al, 2015;. The impact assessments are resource-intensive and usually subject to uncertainties related to the choice of hydrological model, GCMs, emissions scenarios, and downscaling techniques (Vano et al, 2014(Vano et al, , 2015.…”

“…Schaake (1990) made the first attempt to introduce the concept of elasticity and related the climate elasticity of R to precipitation (P ). Since then numerous climate elasticity methods have been developed for evaluating the hydrologic response to climate change all over the world (Schaake, 1990;Dooge et al, 1999;Sankarasubramanian et al, 2001;Milly and Dunne, 2002;Fu et al, 2007;Zheng et al, 2009;Ma et al, 2010;Yang and Yang, 2011;Yang et al, 2014;Vano et al, 2015). Sankarasubramanian et al (2001) provided a detailed category of climate elasticity methods for modelling climate change impacts.…”